Sustainable biofuels from forest and agriculture

May 5, 2010 – Ecological scientists review the promise of switchgrass, the
challenges for forests, and the costs of corn grain-based ethanol production in
three new biofuels and sustainability reports. Produced by the Ecological
Society of America (ESA), the United States’ largest organization of ecological
scientists, and sponsored by the Energy Foundation, these reports explore the
production and use of biofuels from an ecological perspective.

Sustainable biofuels are based on production that does not negatively affect energy flow,
nutrient cycles, and ecosystem services. Many options are being explored for
biofuel production, and the reports address the implications of producing
biofuels from forests, grasslands, rangelands, and agricultural systems and the
likely effects on water, soil, and the atmosphere.

Sustainable Biofuels from Forests

Marilyn Buford and Daniel Neary from the U.S. Forest Service outline the challenges
surrounding the production of sustainable biofuels from woody biomass,
including balancing energy demands with water production, wildlife habitat, and
carbon sequestration in Sustainable Biofuels from Forests: Meeting the
Challenge.

Woody biomass from forests can be converted to biofuels, biobased products, and
biopower through thermochemical, biochemical, and direct combustion methods.
The researchers suggest that 334 million dry tonnes of forest wastes and
residues could be produced each year on a sustainable basis in the United
States. These residues and wastes would come from logging activities,
processing mills, pulp and paper production, and other sources.

Grasslands, Rangelands, and Agricultural Systems

In Grasslands, Rangelands, and Agricultural Systems, scientists Rob Mitchell, Linda
Wallace, Wallace Wilhelm, Gary Varvel, and Brian Wienhold discuss sustainable
biofuel options in grasslands and rangelands that dominate the middle region of
the United States. They specifically address recent interest from policymakers
and energy producers in switchgrass for bioenergy, and the effects this
perennial crop has on soil and water.

“Switchgrass has garnered a lot of attention as a potentially efficient, profitable, and
environmentally friendly biofuel crop,” says Rob Mitchell from the U.S.
Department of Agriculture, Agricultural Research Service. "It is known for
its environmental advantages on marginal cropland like reducing inputs,
controlling erosion, sequestering carbon, and enhancing wildlife habitat. But
there is an array of factors to consider. For example, switchgrass roots run
deeper than other crops, so deep soil samples are required to determine the
exact amount of fertilizer to be applied to prevent nutrient run-off.
Therefore, switchgrass, as with all biofuel crops, will require innovative and
site-specific management practices in order to be economically and
environmentally sustainable.”

Growing Plants for Fuel

Growing Plants for Fuel: Predicting Effects on Water, Soil, and the Atmosphere, authored by Philip
Robertson, Stephen Hamilton, Stephen Del Grosso, and William Parton, reviews
the trade-offs associated with gasoline blended with corn grain-based ethanol.
They describe the consequences of this particular biofuel on the atmosphere,
marine and freshwater ecosystems, wildlife habitats, and the area of land
available for food production.

The researchers also discuss the potential benefits of cellulosic feedstocks such
as woody biomass and switchgrass as alternative biofuel feedstocks that could
avoid many of the downsides of grain-based biofuel crops such as corn.

These three reports join an additional report published in January called Biofuels:
Implications for Land Use and Biodiversity. In that ESA report, scientists
Virginia Dale, Keith Kline, John Wiens, and Joseph Fargione review current
research on biofuel production and its potential effects on ecosystems. They
also analyze the social, economic, and ecological challenges of biofuel
production and the most effective routes to developing sustainable, renewable
fuel alternatives. All four reports are available online at www.esa.org/biofuelsreports/. The final report in
the series, a synthesis of the ecological dimensions of biofuel production,
will be published later in 2010.